The present invention relates to a process for making predominantly soap based bars having about 6% by wt. or more (up to about 13% by wt.) of specific oils (i.e., triglyceride oils) which both process well (e.g., as measured by bar integrity, yield/++-stress) and retain desirable users properties (e.g., lather) as per specifically defined tests.
Traditionally, emollient oils (e.g., mineral oils, silicones, emollients esters) have been incorporated into soap bars at relatively low levels, or, less that 5.0% by wt. Higher levels are generally avoided to avoid problems in processability and/or in user properties (e.g., mineral oils lather poorly). At such levels, however, there is little discernible sensory effect. Typical of such bars having emollient levels of up to 5% is U.S. Pat. No. 5,952,276 to de Ferran et al.
One reason why higher oils levels have not been used is because it has been traditionally difficult to add such high levels during soap milling step (i.e., the point in processing when other additives, such as colorants or odorants, have been added) or any time after cooling and when, accordingly, solidification has begun.
Theorizing that the difficulty of adding high levels of additives to bar at the milling step may be correlated to difficulties arising once crystal structure has formed, U.S. Pat. No. 3,814,698 to Ferrara et al. and U.S. Pat. No. 3,941,712 to Ferrara et al., disclose compositions having much higher levels of xe2x80x9cbath oilxe2x80x9d wherein the bath oil is added at bar saponification step (when ingredients are liquid) rather than milling step.
In both Ferrara patents, the bath oil is broadly defined to include materials such as oils, esters, waxes, long chain alcohols etc. No one material or class is identified as better than another and the only caveat is that, in order to incorporate the amounts of bath oil contemplated by the subject invention, the oil should be added at saponification step. As noted, this is believed to have something to do with the fact that there is no crystal structure at that point (U.S. Pat. No. 3,814,698 at column 2, lines 66-68).
U.S. Pat. No. 4,582,626 to Ferrara discloses that a slip agent should be added at the same time as the bath oil (column 3, lines 6-12). The slip agent and emollient, however, are again added to the saponification mixture (column 3, lines 14-17). Further, again no one material is said to be better than another.
Unexpectedly applicants have found that, if specific emollient oils are chosen (e.g., sunflower oil, castor, palm kernel oil, corn, olive, safflower, cottonseed and/or mixtures thereof), relatively large amounts (e.g., 6% by wt. to 13% of oil) may be incorporated.
While not wishing to be bound by theory, it is believed the selected oils are readily absorbed into the mortar liquid crystal phase such that they do not form separate phase (which could interact with soap and disrupt processing properties such as bar integrity or yield stress) and, at the same time, are readily delivered from the bar to provide good user properties.
Thus, in one embodiment, this invention relates to a predominantly soap bar comprising about 59 to 84% soap, 0 to 10% non-soap, non-triglyceride agents (e.g., filler, processing aids, cost reducing agents, skin conditioning agents, none of which categories are necessarily exclusive of the others), 10 to 18% water and 6 to 13% triglyceride oil, wherein said triglyceride oil is added directly at finishing stage, post crystallization such that combination of components yields bar with minimal yield stress of about 90, preferably about 100 and lather volume of at least about 65%, preferably at least 70% relative to bars of the soap base.
In a second embodiment (that of subject specification), the invention relates to a process for making a bar comprising predominantly soap (59% to 84% soap), 0 to 10% non-soap, non-triglyceride agents and 10 to 18% water wherein said bar has minimal yield stress of about 90, preferably about 100 and lather volume of at least about 65%, preferably at least 70% of the soap base, wherein said process comprises adding about 6% to 13% triglyceride oil to the bar at a finishing stage when other components have already crystallized
In one embodiment, the invention provides a bar composition comprising:
(a) 59 to 84% by wt. soap;
(b) 0 to 10% by wt. of non-soap non-triglyceride agents (for example, used to enhance processing, reduce costs and/or improve skin conditioning) (examples of such agents include fillers, glycerin, PEG, polymers, free fatty acids, synthetic surfactants);
(c) 10 to 18% by wt. water; and
(d) 6 to 13% triglyceride oil, wherein oil is added directly at finishing stage post crystallization such that said bar has minimal yield stress of about 90, preferably 100 and lather volume of at least about 65% relative to base bar.
In a second embodiment, the invention provides a process for making a bar comprising:
(a) 59 to 84% by wt. soap;
(b) 0 to 10% non-soap, non-triglyceride agents; and
(c) 10 to 18% water,
wherein said bar has minimal yield stress of about 90, preferably 100 and lather volume of at least 65% relative to base bar, wherein said process comprises adding 6% to 13% triglyceride oil to the bar at a finishing stage when other bar components have already crystallized.
The present invention relates to process for making compositions comprising relatively large amounts of triglyceride oils. The oils can be incorporated at a point beyond the saponification stage (i.e., they can be incorporated at finishing stage, post crystallization) without hindering processing (as measured, for example by yield stress and bar integrity) and while retaining desirable consumer attributes (e.g., lathering).
In one embodiment, the invention relates to compositions, e.g., soap based compositions, comprising specific emollient oils. Unexpectedly, it has been found that when certain oils (i.e., triglyceride emollients) are incorporated into bars at the so-called xe2x80x9cfinishingxe2x80x9d steps of bar preparation (i.e., once bars have reached stage where soap noodles are fully crystallized), certain benefits are found. Specifically, when incorporated at this finishing stage, the triglyceride oils process well while providing good lather as defined.
The bar composition of the invention comprises 59% to 84%, preferably 70 to 80% by wt. soap.
The term xe2x80x9csoapxe2x80x9d is used herein in its popular sense, i.e., the alkali metal or alkanol ammonium salts of aliphatic, alkane-, or alkene monocarboxylic acids. Sodium, potassium, magnesium, mono-, di- and tri-ethanol ammonium cations, or combinations thereof, are suitable for purposes of this invention. In general, sodium soaps are used in the compositions of this invention, but from about 1% to about 25% of the soap may be potassium or magnesium soaps. The soaps useful herein are the well known alkali metal salts of natural of synthetic aliphatic (alkanoic or alkenoic) acids having about 8 to 22 carbon atoms, preferably about 8 to about 18 carbon atoms. They may be described as alkali metal carboxylates of acrylic hydrocarbons having about 8 to about 22 carbon atoms.
Soaps having the fatty acid distribution of coconut oil may provide the lower end of the broad molecular weight range. Those soaps having the fatty acid distribution of peanut or rapeseed oil, or their hydrogenated derivatives, may provide the upper end of the broad molecular weight ranges.
It is preferred to use soaps having the fatty acid distribution of coconut oil or tallow, or mixtures thereof, since these are among the more readily available fats. The proportion of fatty acids having at least 12 carbon atoms in coconut oil soap is about 85%. This proportion will be greater when mixtures of coconut oil and fats such as tallow, palm oil, or non-tropical nut oils or fats are used, wherein the principle chain lengths are C16 and higher. Preferred soap for use in the compositions of this invention has at least about 85% fatty acids having about 12 to 18 carbon atoms.
Coconut oil employed for the soap may be substituted in whole or in part by other xe2x80x9chigh-alluricxe2x80x9d oils, that is, oils or fats wherein at least 50% of the total fatty acids are composed of lauric or myristic acids and mixtures thereof. These oils are generally exemplified by the tropical nut oils of the coconut oil class. For instance, they include: palm kernel oil, babassu oil, ouricuri oil, tucum oil, cohune nut oil, muru-muru oil, jaboty kernel oil, khakan kernel oil, dika nut oil and ucuhuba butter.
A preferred soap is a mixture of about 30% to about 40% coconut oil and about 60% to about 70% tallow. Mixtures may also contain higher amounts of tallow, for example, 15% to 20% coconut and 80% to 85% tallow.
The soaps may contain unsaturation in accordance with commercially acceptable standards. Excessive unsaturation is normally avoided.
Soaps may be made by the classic kettle boiling process or modern continuous soap manufacturing processes wherein natural fats and oils such as tallow or coconut oil or their equivalents are saponified with an alkali metal hydroxide using procedures well known to those skilled in the art. Alternatively, the soaps may be made by neutralizing fatty acids, such as lauric (C12), myristic (C14), palmitic (C16), or stearic (C18) acids with an alkali metal hydroxide or carbonate.
The bar compositions may optionally comprise 0% to 10% by wt. of optional components which are neither glyceride, soap or water. If synthetic surfactant is used, it may be selected form the group consisting of anionic, nonionic, amphoteric/zwitterionic and cationic surfactants.
Anionic may be an aliphatic sulfonate (e.g., C8 to C22 alkane sulfonate or disulfonate; or aromatic sulfonate), alkyl sulfate, alkyl ether sulfate, alkyl sulfosuccinate, alkyl or acyl taurate, alkyl or acyl sarcosinates or any of the anionics described, for example, in U.S. Pat. No. 5,916,856 to Massaro et al., hereby incorporated by reference into the subject application.
Similarly amphoterics, nonionics and cationics may be any of the surfactants described in U.S. Pat. No. 5,916,856 to Massaro et al.
Other agents which may be used include processing aid (e.g., filler) or conditioning agents (e.g., PEG, free fatty acid or glycerin).
Other additives which may be used include one more of the following preservatives: perfumes, colors, opacifiers, optical brighteners, germicides.
The bar also comprises 10 to 18% by wt., preferably 10 to 15% by wt. water.
Finally, the compositions comprise 6% to 13% by wt. of triglyceride oil.
Examples of triglycerides which may be used include apricot oil, sunflower seed oil, avocado oil, castor oil, cottonseed oil, palm kernel oil, safflower oil, corn oil, soya bean oil, almond oil, wheat germ and/or blends thereof.
The oils of the invention are added in the finishing stages of soap making.
More specifically, milled soaps have been made for many years. It is usual to produce such soaps by liquefying a mixture of fatty acid, or acids, or glycerides thereof, and aqueous sodium hydroxide solution at elevated temperatures; saponifying the fatty acid content of the warm liquid mixture; cooling the saponification mixture to a substantially solid, but suitable soft, condition, forming the solidified saponification mixture into a suitable shape, e.g., by extrusion into a ribbon or the like; drying the shaped extrudate to an acceptable moisture content; milling the dried xe2x80x9csoapxe2x80x9d with conventional additives and adjuvants such as dyes, pigments, perfumes and the like; and then forming the milled soap composition into bars or other desired shapes.
The oils of the invention as noted, are added, at finishing stage, post crystallization.
In a second embodiment of the invention (that of subject specification), the invention comprises a process for making bars comprising soap; non-soap, non-triglyceride components and water in amounts noted above and wherein bar has minimal yield stress and minimal lather volumes as also noted, wherein said process comprises adding 6% to 13% triglyceride oil to the bar at a finishing stage post crystallization of the non-triglyceride components.
It should be noted that other minors (e.g., perfume) may also be added after crystallization as long as at least sufficient components have been added (e.g., soap and structurant) to form a crystallized soap base.
Except in the operating and comparative examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts or ratios of materials or conditions or reaction, physical properties of materials and/or use are to be understood as modified by the word xe2x80x9caboutxe2x80x9d.
Where used in the specification, the term xe2x80x9ccomprisingxe2x80x9d is intended to include the presence of stated features, integers, steps, components, but not to preclude the presence or addition of one or more features, integers, steps, components or groups thereof.
The following examples are intended to further illustrate the invention and are not intended to limit the invention in any way.
Unless indicated otherwise, all percentages are intended to be percentages by weight.